Hereditary multiple exostoses is a familial disturbance in the growth of cartilaginous bone tissue, most marked at the diaphyso-epiphyseal junction of the long bones. Until the report of Ehrenfried (1) in 1917, mention of this disease was relatively infrequent in the American literature, but since that time numerous cases have been reported (2). In a review of the American literature prior to his publication, Ehrenfried was able to find 71 cases, to which he added 12 cases of his own. His contribution was to bring this condition to the attention of the medical profession in this country. The nomenclature is confusing. In Britain, where the disease was popularized by Keith (6), it is referred to as “diaphyseal aclasia.” Ehrenfried and others in this country preferred “hereditary deforming chondrodysplasia,” a vague term which does not describe the actual findings. “Hereditary multiple exostoses,” as proposed by Jaffe (3), appears to give the most accurate description of the disorder and because of its simp...